Menggunakan merge..output untuk mendapatkan pemetaan antara source.id dan target.id

Menurut pendapat saya ini adalah penggunaan MERGE dan output yang bagus. Saya telah menggunakan beberapa skenario dan belum mengalami keanehan apa pun hingga saat ini. Sebagai contoh, berikut adalah pengaturan pengujian yang mengkloning Folder dan semua File (identitas) di dalamnya ke dalam Folder (panduan) yang baru dibuat.

DECLARE @FolderIndex TABLE (FolderId UNIQUEIDENTIFIER PRIMARY KEY, FolderName varchar(25));
INSERT INTO @FolderIndex 
    (FolderId, FolderName)
    VALUES(newid(), 'OriginalFolder');

DECLARE @FileIndex TABLE (FileId int identity(1,1) PRIMARY KEY, FileName varchar(10));
INSERT INTO @FileIndex 
    (FileName)
    VALUES('test.txt');

DECLARE @FileFolder TABLE (FolderId UNIQUEIDENTIFIER, FileId int, PRIMARY KEY(FolderId, FileId));
INSERT INTO @FileFolder 
    (FolderId, FileId)
    SELECT  FolderId, 
            FileId
    FROM    @FolderIndex
    CROSS JOIN  @FileIndex;  -- just to illustrate

DECLARE @sFolder TABLE (FromFolderId UNIQUEIDENTIFIER, ToFolderId UNIQUEIDENTIFIER);
DECLARE @sFile TABLE (FromFileId int, ToFileId int);

-- copy Folder Structure
MERGE @FolderIndex fi
USING   (   SELECT  1 [Dummy],
                    FolderId, 
                    FolderName
            FROM    @FolderIndex [fi]
            WHERE   FolderName = 'OriginalFolder'
        ) d ON  d.Dummy = 0
WHEN NOT MATCHED 
THEN INSERT 
    (FolderId, FolderName)
    VALUES (newid(), 'copy_'+FolderName)
OUTPUT  d.FolderId,
        INSERTED.FolderId
INTO    @sFolder (FromFolderId, toFolderId);

-- copy File structure
MERGE   @FileIndex fi
USING   (   SELECT  1 [Dummy],
                    fi.FileId, 
                    fi.[FileName]
            FROM    @FileIndex fi
            INNER
            JOIN    @FileFolder fm ON 
                    fi.FileId = fm.FileId
            INNER
            JOIN    @FolderIndex fo ON 
                    fm.FolderId = fo.FolderId
            WHERE   fo.FolderName = 'OriginalFolder'
        ) d ON  d.Dummy = 0
WHEN NOT MATCHED 
THEN INSERT ([FileName])
    VALUES ([FileName])
OUTPUT  d.FileId,
        INSERTED.FileId
INTO    @sFile (FromFileId, toFileId);

-- link new files to Folders
INSERT INTO @FileFolder (FileId, FolderId)
    SELECT  sfi.toFileId, sfo.toFolderId
    FROM    @FileFolder fm
    INNER
    JOIN    @sFile sfi ON  
            fm.FileId = sfi.FromFileId
    INNER
    JOIN    @sFolder sfo ON 
            fm.FolderId = sfo.FromFolderId
-- return    
SELECT  * 
FROM    @FileIndex fi 
JOIN    @FileFolder ff ON  
        fi.FileId = ff.FileId 
JOIN    @FolderIndex fo ON  
        ff.FolderId = fo.FolderId